Hello sir,pls let me know ur age first . Is flash light started recently and how many times you saw it and duration,is more important. Was flash light having any colour and shape ? Are you wearing high number spects and if yes since how many days ? All these questions are very important to decide prognosis. If flash light persist for a long time and having particular color and shape and associated with headache,it may cause in migraine. But if its short duration ,then you should go for detailed eye check up to rule out posterior segment pathology in eye like vitreous or retinal detachment.Many flash lights are without any pathology so nothing to worry for such episodes.